The invention disclosed herein relates generally to verifying communications paths on a network. More particularly, the present inventions relate to the establishment of a connection of a Voice of Internet Protocol (VoIP) call to verify that a set of one or more given endpoints are available to receive a call.
The Open Systems Interconnection (OSI) specification provides a “reference model” for how messages should be transmitted between any two points in a telecommunication network. The purpose of the model is to guide product technology implementors so that their products will consistently work with other products. The reference model defines seven layers of functionality that take place at each end of a communications link. Layer 3 (L3) refers to the network layer of the model, which is concerned with knowing the address of neighboring nodes in a network, selecting routes and quality of service, and recognizing and forwarding to the transport layer incoming messages destined for the local host. An Internet Protocol (IP) address is one example of a layer 3 address.
Ping (Packet Internet or Inter-Network Groper) is a tool used to verify that a given IP address exists and can accept requests. Users and software processes employ Ping to diagnostically ensure that a host computer that the user is attempting to reach is actually operating. Ping may also be used to communicate with an operating host in order to determine the amount of time required to receive a response from the host, as well as other related statistics. The Ping software utility sends an Internet Control Message Protocol (ICMP) packet to a specified IP network address or a qualified domain name. ICMP is an extension to the IP protocol that supports packets with error, control and informational messages. The utility waits for replies from the address in response to receipt of the ICMP packet. In addition to the data described above that is provide by Ping, the software is useful in troubleshooting Internet connections as well as determining the quality of a network connection.
In the realm of IP telephony or VoIP, however, no equivalent to the Ping utility exists whereby users may receive information regarding the ability of a host to respond to a VoIP call, the ability of the network to route VoIP packets, or the quality of the network connection. Furthermore, conventional Ping utilities provide information regarding L3 connectivity, but not whether high layer applications are working, which is important in the realm of VoIP telephony.
There is thus a need for a system and method that provides an application layer test that also provides information regarding the availability or operation of higher layer network services, e.g., VoIP telephony services.